相关论文: Sub-structure formation in starless cores

Star formation is intimately linked to the dynamical evolution of molecular clouds. Turbulent fragmentation determines where and when protostellar cores form, and how they contract and grow in mass via accretion from the surrounding cloud…

A fundamental issue in star formation is understanding the precise mechanisms leading to the formation of prestellar cores, and their subsequent gravitationally unstable evolution. To address this question, we carefully construct a suite of…

We test the hypothesis that the starless cores may be gravitationally bound clouds supported largely by thermal pressure by comparing observed molecular line spectra to theoretical spectra produced by a simulation that includes…

(Abridged). We present numerical simulations of isothermal, MHD, supersonic turbulence, designed to test various hypotheses frequently assumed in star formation(SF) theories. We consider three simulations, each with a different combination…

We analytically investigate the modes of gravity-induced star formation possible in idealized finite molecular clouds where global collapse competes against both local Jeans instabilities and discontinuous edge instabilities. We examine…

For a number of starless cores, self-absorbed molecular line and column density observations have implied the presence of large-amplitude oscillations. We examine the consequences of these oscillations on the evolution of the cores and the…

Turbulent fragmentation determines where and when protostellar cores form, and how they contract and grow in mass from the surrounding cloud material. This process is investigated, using numerical models of self-gravitating molecular cloud…

The isothermal gravitational collapse and fragmentation of a region within a molecular cloud and the subsequent formation of a protostellar cluster is investigated numerically. The clump mass spectrum which forms during the fragmentation…

In the early Universe, large-scale flows were omnipresent, and the flow collisions produced sheets and filaments. This phenomenon occurs for both particle and wave dark matter. But for the latter, these sheets and filaments are the…

The isothermal dynamical evolution of a clumpy and turbulent molecular cloud region and its fragmentation into a protostellar cluster is investigated numerically. The effect of different initial density and velocity distributions, generated…

We present a unified model for molecular core formation and evolution, based on numerical simulations of converging, supersonic flows. Our model applies to star formation in GMCs dominated by large-scale turbulence, and contains four main…

We present a comprehensive study of MHD waves and instabilities in a weakly ionised system, e.g., an interstellar molecular cloud. We determine all the critical wavelengths of perturbations across which the sustainable wave modes can change…

The convection that takes place in the innermost shells of massive stars plays an important role in the formation of core-collapse supernova explosions. Upon encountering the supernova shock, additional turbulence is generated, amplifying…

The isothermal gravitational collapse and fragmentation of a molecular cloud region and the subsequent formation of a protostellar cluster is investigated numerically. The clump mass spectrum which forms during the fragmentation phase can…

Turbulent fragmentation determines where and when protostellar cores form, and how they contract and grow in mass from the surrounding cloud material. Molecular cloud regions without turbulent driving sources, or where turbulence is driven…

We study the linear evolution of small perturbations in self-gravitating fluid systems with magnetic fields. We consider wave-like perturbations to nonuniform filamentary and sheet-like hydrostatic equilibria in the presence of a uniform…

This letter presents a numerical study of the evolution of an emission line cloud of initial density 10 cm$^{-3}$, temperature $10^4$ K, and size 200 pc, being overtaken by a strong shock wave. Whereas previous simple models proposed that…

We performed simulations of self-gravitating hydrodynamic turbulence to model the formation of filaments, clumps and cores in molecular clouds. We find that when the mass on the initial computational grid is comparable to the Jeans mass,…

We suggest that molecular cloud (MC) turbulence is a consequence of the very process of MC formation by collisions of larger-scale flows in the diffuse atomic gas, which generate turbulence in the accumulated gas through bending- mode…

The well-known Jeans criterion describes the onset of instabilities in an infinite, homogeneous, self-gravitating medium supported by pressure. Most realistic astrophysical systems, however, are not isolated - instead they are under the…